G5.22 Be careful with the
sign conventions for the angles. See LB pages
902/903 for a careful discussion. Griffths is NOT careful in
Example 5.5 and ends up with a non-standard convention for the signs in
5.35. Compare with LB 28.5 which uses the standard convention.
G5.41 You will need to
assume that the particle's initial velocity has no z-component.